"It was a horrible thing to witness. This was totally botched," said Lockett's attorney, David Autry.

He added that it was clear from the outset that the execution was handled poorly.

"They should have anticipated possible problems with an untried execution protocol," Autry said. "Obviously the whole thing was gummed up and botched from beginning to end. Halting the execution obviously did Lockett no good."

In response to this incident, Governor Mary Fallin ordered a 14-day stay of execution for an inmate who was scheduled to die two hours after Lockett.

The execution began at 6:23 p.m., when officials began administering the drug midazolam. A doctor declared Lockett to be unconscious at 6:33 p.m. and Lockett was declared deceased at 7:06 p.m.

The American Civil Liberties Union of Oklahoma called for an immediate moratorium on state executions.

"This evening we saw what happens when we allow the government to act in secret at its most powerful moment and the consequences of trading due process for political posturing," said ACLU executive director Ryan Kiesel.